In many countries soldiers serving in specific occupations are referred to by terms other than their occupational name. For example, military police personnel in the British Army are known as "red caps" because of the colour of their caps (and berets).

Infantry are sometimes called "grunts" (in the United States Army or United States Marine Corps) or "squaddies" (in the British Army), while U.S. Army artillery crews, or "gunners," are sometimes referred to as "redlegs", from the service branch color for artillery.[citation needed] U.S. soldiers are often called "G.I.s" (short for the term "General Issue"). Members of the Marine Corps are typically referred to as "marines" rather than "soldiers".[3]

In the United States, the term warfighter is often used to refer collectively to all whose job it is to do the actual fighting, although in 2011 the U.S. Army officially started calling its combat personnel soldiers instead of warfighters, in part to avoid confusion among "warfighters" assigned to peace-keeping or other types of duties beyond combat activities.[4] The army has not completely phased out this terminology and still uses "warfighter" in various contexts such as the Project Manager Warfighter Information Network-Tactical.

French Marine Infantry are called marsouins (French: porpoises) because of their amphibious role.[citation needed] Military units in most armies have nicknames of this type, arising either from items of distinctive uniform, some historical connotation or rivalry between branches or regiments.

Some soldiers, such as conscripts or draftees, serve a single limited term. Others choose to serve until retirement; then they receive a pension and other benefits. In the United States, military members can retire after 20 years.[5] In other countries, the term of service is 30 years, hence the term "30-year man".

^Patton, Mark (2011-08-14). "Wordsmiths take aim at simplifying acronyms for Army". Stars and Stripes. Retrieved 2015-07-23. Citing the potential for ambiguity in meaning of term "warfighter" (which could, like the term "firefighter" be read to mean "one who fights to stop or prevent wars").